This rare earth oxide appears not to be a valid species, but rather a variety of Rutile. It is closely related to Ilmenorutile, however the presence of Tantalum makes gives a very unique chemistry. This particular specimen is a superb example of this very rare mineral featuring a pair of dark black, well formed, exceptionally large crystals measuring up to 1.2 cm in Quartz matrix. A really unique and hard to find display quality specimen. 4.0 x 2.8 x 2.6cm